Tenergy TLP-4000 Universal 1A Smart Charger for Li-Ion/Polymer Battery Pack (3.7V-14.8V 1-4 Cell) Charge from 1-4 cells Li-Ion battery pack or Li-Polymer battery pack with capacity more than 1000mAh. Only use this charger for battery packs with built-in protection circuit. Never use it for hobby packs (RC, airsoft, etc) which are unprotected and are designed to be balance-charged. The charger will cut off automatically if battery is fully charged. 100V-240V AC input for worldwide power support. This smart charger can auto-switch output. Safety protection: Over Voltage protection; Short Circuit protection; Polarity error protection. Buy with confidence, your charger includes a 12-month warranty.